John Mastoras is the Toronto chair of our Canadian employment and labour law group. He is known to his clients as a passionate and dedicated advocate and business partner who provides innovative and practical advice.
John is frequently called upon to litigate highly contentious matters such as disruptive labour disputes and workplace mental health issues, and acts exclusively for employers in the broader area of labour and employment law. He regularly provides representation and advice in connection with grievance arbitrations, labour relations board disputes, human rights proceedings, occupational health and safety charges, workers’ compensation, labour injunctions and common law employment actions. His practice spans unionized and non-unionized workplaces for both federally and provincially regulated employers.
John has litigated on behalf of and provided strategic advice to a broad group of employers and employer associations in various industries, including energy, pulp and paper, pharmaceutical, health care, insurance, long-shoring, construction, food processing, transportation, steel, automotive and manufacturing more generally. He is often in the forefront as chief spokesperson in collective agreement negotiations and provides helpful counsel in this regard to a variety of employers.
For the past 19 years, John has taught at the University of Toronto’s Centre for Industrial Relations and Human Resources, where he is an adjunct professor, and publishes frequently in all areas of employment and labour law. He is the recipient of the 2009 Morley Gunderson Prize conferred by the University of Toronto's Centre for Industrial Relations and Human Resources. The prize is awarded annually to a graduate of the Centre for Industrial Relations who combines outstanding professional achievement with significant service to the university.
Year of call
LL.B., Osgoode Hall Law School, 1987
M.I.R., University of Toronto, 1984
B.A.(Hons.), University of Toronto, 1981
- “The Road to Understanding Recent Labour and Employment Law Developments,” Ontario Trucking Association, February 15, 2007.
- “The Disabled Employee: Accommodation and Frustration of Contract,” Ogilvy Renault, June 7, 2006.
- “Managing Absenteeism and Disabilities in the Unionized Workplace,” ORC Worldwide, May 31, 2006.
- “Labour/Employment Law Hot Button Issues - Overview of the Shifting Landscape,” Ontario Trucking Association, February 16, 2006.
- “Employer Alert: Bill 144 Automatic Certification, Bill C-45 Criminalization of Health and Safety Laws, and More,” International Warehouse Logistics Association, May 25, 2005.
- “Recent Developments in Labour Arbitration,” Innovative Responses to the Emerging Issues in Human Resources and Industrial Relations, Centre for Industrial Relations, October 4, 2002.
- “Ten Paths to Enlightenment - Topical Legal Issues for Employer Executives,” Zen and the Art of Employee Maintenance: Young Presidents’ Organization, November 2001.
- “Accommodating Religious Needs in the Workplace,” The Duty to Accommodate in the Unionized Workplace, Workchannel, Centre for Labour-Management Development, April 5, 2001.
- “Monitoring and Surveillance,” Infonex on Human Rights and Privacy in the Workplace, January 1997.
- “Recent Trends in Workers’ Compensation Adjudication: Stress and Environmental Illness,” Major Benefits Developments, Federated Press on Human Resource Executives Conference, September 1995.
Rankings and recognitions
- Best Lawyers in Canada (2015-2017): Labour and Employment Law
- Canadian Legal Lexpert Directory (2012-2016): recommended in Workers' Compensation - Employer
- Canadian Legal Lexpert Directory (2016): recommended in Labour Relations - Management
- Recipient of the 2009 Morley Gunderson Prize conferred by the University of Toronto’s Centre for Industrial Relations and Human Resources. The prize is awarded annually to a graduate of the Centre for Industrial Relations who combines outstanding professional achievement with significant service to the Centre.
- PLC Which lawyer? (2011): Labour and employment
Memberships and activities
- Canadian Bar Association
- Law Society of Upper Canada
- The Advocates’ Society
- HR Policy Association (US)
- American Bar Association
Our team of leading management-side labour and employment lawyers will examine current developments in the law at our Annual Workplace Law Conference..
May 9, 2017
Stay informed with our Employment and Labour – 2016 Year in Review. This report provides an up-to-date compilation of the latest developments in E&L, enabling human resource managers, legal counsel, and business leaders .
March 07, 2017
With the Christmas season around the corner, many are looking forward to the statutory holidays..
November 28, 2016